I also found out that Swest has a “Paste” copper solder…which
is a Plumbers solder. The book that I have access to states
this:

Copper Solder Paste

Solder copper, brass, nickel and bronze, no additional flux is
required. Paste contains no cadmium or antimony. Flows at 430
degrees F. Ship. wt. .20 lb This cost $5.00 each. Is this a
good idea…the paste I mean. Would any of you consider this
price for this amount a good deal, for the paste?

I found an Rio-Grande book, the High Copper Wire Solder sells
for $13.95 fo r 1-2 lbs…which is very much cheaper than the
Swest.

But has anyone worked with solder paste? What is the
difference, if any???

Hi Carol, If the solder flows at 450, it is a low tempature
solder and not a silver solder. It may or may not be suitable
for what you want it to do.Copper can be hard to solder because
of its quickness to oxidize and its heat conductivity. Marilyn
Smith